Confidence: I'm as sure as I can be.
Notes: This one thankfully is one of the more readily identifiable caddis(many are a lot more difficult). The dark markings within the apical cells at the rear of the forewing form well defined streaks. In H. digitatus they are more branched creating a mottled effect. There are only 2 Halesus species to pick from in Britain. Info from The Adult Trichoptera of Britain and Ireland, Basrnard and Ross 2012.